This invention relates generally to ingot pusher furnaces and more particularly, it relates to an improved pusher furnace which includes means for reducing heat loss from the charging and discharging ends of the furnace so as to produce a more efficient and uniform heating of the ingots.
A prior art furnace 10 is illustrated in FIG. 1 of the drawings and has been labeled "Prior Art." As can be seen, the rails 36 used for support and movement of a plurality of aluminum ingots 38 to be heated into and out of the enclosure 20 actually extend beyond charging end 17 and discharging end 19 of the furnace 10. As a result, there is created a difficult problem in obtaining an efficient sealing of the furnace. The bottoms of the charging door 24 and discharging door 28 in their closed positions will come to rest on the top surface of the rails 36. Thus, there is a great likelihood of outside cold air to leak into the furnace around the rails at the locations where they extend through the respective door openings.
Such influx of cold air has a tendency to upset the temperature uniformity by causing a cold spot or "chill" to be formed on the next ingot to be discharged, which means that the quality of the finished rolled aluminum has been sacrificed. Further, heat loss from the furnace due to the leaks will mean the wasting of energy, thereby reducing its overall efficiency.
It would therefore be desirable to provide an improved ingot pusher furnace which includes means for reducing heat loss from the charging and discharging ends of the furnace so as to produce a more efficient and uniform heating of the ingots. This is accomplished in the present invention by the provision of support rails that terminate inside of the charging and discharging doors and by fabricating the doors to extend below the support rails, thereby creating a positive seal on each side of the doors.